The new source HESS J1641-463 emerging near HESS J1640-465

October 2012

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fig0
Radio image of the vicinity of the gamma ray source HESS J1640-456, with the two remnants G338.3-0.0 and G338.5+0.1. 843 MHz image from the Sydney University Molonglo Sky Survey.

With increasing exposure and statistics in the Galactic plane, complex gamma-ray sources are better resolved and frequently new structures appear. This is the case for a new source in the vicinity of the strong gamma ray source HESS J0632+057 However, no variability is detected in the gamma ray flux. Deeper X-ray observations covering the field will help to reveal the nature of this new source, for example by exposing an X-ray pulsar wind nebula as seen in other H.E.S.S. sources, e.g. in


fig1
Fig. 1: Very high energy gamma ray map of the field around HESS J1640-465 / HESS J1641-463, for gamma rays about 4 TeV. Black solid contours indicate the significance of the emission at the 5, 6, 7 and 8 sigma level. The inset illustrates the point spread function, i.e. the angular resolution of the instrument. The red box indicates the slices through the gamma ray images, shown in Fig. 2.
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Fig. 2: Distribution of gamma ray flux along the slice indicated in Fig. 1, for different energy bands: all energies, and above 1, 2, 3, 4 and 5 TeV. The full lines model the distribution as a superposition of two sources with a Gaussian intensity distribution. Dashed vertical lines indicate the centers of the two radio supernova remnants. A single Gaussian source (dashed Gaussians) is not compatible with the data.
fig2
Fig. 3: Radio view (MOST 843 MHz) of the field of G338.5+0.1 and G338.3-0.0. The 6, 7 and 8 sigma significance contours of the gamma ray emission > 4 TeV are shown as black contours. The catalog position and extension of G338.5+0.1 is indicated as a dashed black circle, the best fit position of HESS J1641−463 is shown as a black cross. The positions of nearby HII regions, of SNR G338.3-0.0 and of HESS J1640-465 are also indicated.